Concentration control system



Nov..27, 1951 J. K. FARRELL ETAL 2,576,253

CONCENTRATION CONTROL SYSTEM Filed March 11, 1946 2 SHEETS-SHEET 1INVENTOR James firuzeZ/z Farrell Paa)! Ajfeene Nov. 27, 1951 J. K.FARRELL VET AL CONCENTRATION CONTROL SYSTEM 2 SHEETS-SHEET 2 Filed March11, 1946 v INVENTOR James flxzneih Farm awl AJfeene BY Z ATTO NEYPatented Nov. 27, 1951 CONCENTRATION CONTROL SYSTEM James K. Farrell andPaul A. Keene, Syracuse,

N. Y., assignors to Allied Chemical & Dye Corporation, a corporation ofNew York Application March 11, 1946, Serial No. 653,475

Claims. (Cl. 137-78) This invention relates to a detergent dispenser,

and more particularly to a detergent dispenser for washing machines suchas dish or can washing machines.

One type of dispenser heretofore used for can and dish washing machineshas required the compressing of the detergents into hard pellets ortablets which were placed in the dispenser, and water then drippedslowly thereover, the rate of Water feed being adjusted to supply thenormal demand for the detergent. Other types involved the formation ofsolutions of the detergent and the addition of such solution to thewashliquid by operation of a valve actuated by movement of the cans ortrays of dishes, ,or the addition of such solution by allowing it toflow by gravity from a tank to the body of wash liquid. Still anothertype of dispenser involved the disposition of the solid detergent in aperforated container over which a stream of water continually flows, thedrip from this container flowing into the body of wash solution. Thesedispensers have generally been unsuccessful for a number of reasons,among which may be mentioned:

(1) The rate at which detergent is consumed in the operation of thewashing machines varies, widely in some cases, during the course ofnormal operation; hence, all dispensers which operate on a fixed rate ofaddition are unsatisfactory because they result in the concentration ofthe detergent in the wash solution varying widely.

For best results the concentration of detergent in the wash solutionshould be maintained within fairly narrow limits; concentrations belowthe predetermined limit produce ineflicient washing, and concentrationsabove this limit result in unnecessarily large losses of detergents;

, (2) When solutions are added from a tank,

the rate of addition constantly changes due'to struction and hencerelatively inexpensive; in-

volves few moving parts so that the maintenance cost is small; canreadily be installed upon any can or dish washer by an ordinarymechanic,

without special tools, in a very short time; is so designed thatplugging of the discharge conduit or pipe lines by crystallization ofdetergent cannot take place in operation; and is unusually efficient,particularly in that it maintains the concentration of the body of washsolution in the washer within fairly narrow limits. Other objects andadvantages of this invention will be apparent from the followingdetailed description thereof.

In the preferred embodiment illustrated on the drawings, the inventionis shown incorporated in a dish washing machine and the presentdescription will be confined to the present illustrated embodiment ofthe invention. It will be understood, however, that the novel featuresand improvements are susceptible to other applications such, forexample, as can washing machines or other machines in which it isdesired to maintain within narrow limits the concentration p f asolution which tends to foam in use. Hence,

the scope of this invention is not confined to th sprays 24, 25. 5

embodiment herein described.

In the accompanying drawings,

Fig. l is a diagrammatic vertical section, partly in elevation,illustrating a conventional type of dish washing machine with which thedispenser of this invention may be used, the dispenser being showndiagrammatically, and one possible location of the dispenser relative tothe washer being depicted;

Fig. 2 is a wiring diagram showing a bridgetype of electrical controlwhich may be used to control the operation of the dispenser embodyingthis invention; v r V Fig. 3 is a plan view partly broken away to showthe interior structure of a dispenser embodying this invention; and v IFig. 4 is a vertical section partly in elevation, which section isbroken away to enable showing the parts on a somewhat larger scale thanwould otherwise be possible, of a dispenser embodying this invention. 1w

Referring to Fig. 1, the dish washing machine comprises a housing ID inwhich racks of dishes H are placed on perforated supports [2. 'Top andbottom wash sprays l3, I4 are arranged to be supplied with wash solutionunder pressure through branch pipes l5, 16 from a motor driven pump H,the suction intake l8 of which is in communication with a bodyof'detergent solution 19 disposed in a tank 20 positioned near the bottomof the washing machine. Hot rinse water is supplied from a pipe 2|having branches 22, 23 extending to the top and'bottom rinse It will beunderstood that the washer shown in thendrawing represents one desiredconcentration. The presence of foam between plates 63, 64 in effectshort circuits the control electrode 6|, i. e. materially decreases theresistance in the arm 58'of the'Wheatstone bridge. As shown in Fig. 1,electrode 62 is located at a point above the normal level of body ofsolution l9 where the foam will reach it quickly. Consequently, inoperation the dispensing of detergent solution willbe stopped when foamreaches the electrode 62, which will take place before enough detergentis added to cause the solution to overflow the machine. As soon as thefoam dies down due, for example, to the presence of soil in the washwater, the'electrode 62 is left free and clear, becoming an infiniteresistance, and consequently exerting no further effect on the controlelectrode 6|. 7

Secondary coils 65, 68 of transformer 53 are connected by conductorswith points 66, 6'! of the Wheatstone bridge. Secondary coil 68 suppliescurrent to the filaments 69, 10 of electronic tubes H, 12. Tube Hdesirably is of a conventional triode or pliotron, and tube 12 desirablyis of'a type to produce a higher emission of electrons, such as the wellknown Thyratron. Tube H, as conventional, comprises a cathode 12, a grid13 and an anode 14. The tube 12 comprises a cathode 15, a grid 16, ascreen electrode 11 and an anode 18. a

Secondary coil 19 of the transformer 53 in circuit with points 86, 8| ofthe Wheatstone bridge. Located in this circuit is the grid circuit ofthe tube H as shown in Fig. 2. The output anode circuit of the tube Hincludes a resistance 14 across which the input circuit of the tube 12is shunted. In the output anode circuit of tube 12 is disposed relay 82for operating switch 54 in the main circuit 5|. Resistance 14' is suchthat when the current flowing through the output anode circuit of tube1| reaches a certain value, the potential drop across the resistance 14'causes the tube 12 to pass sufficient current through its anode circuitto operate the relay 82, to close switch 54.

The control circuit hereinabove described, except for the electrodes 6|,62 and the lead wires connected thereto, and the parts of the maincircuit except for the solenoid 48 and signal lamp 55, are allpreferably disposed in a control box 83 which may be positioned onsupport 28 next to dispenser 21. The control is, therefore, readilyapplicable to existing washers not equipped with controls, particularlyin cases where it is desired to supply such washers with dispensers ofthe type herein described. When modifying a washer to embody thisinvention, it is only necessary to install the dispenser and control boxon the side of the washer, connect the discharge of the dispenser withthe washer, and place the electrodes 6|, 64 within the washer in therelative positions shown.

In operation, resistance 51 is set at a point previously determined bycalibration, which point is dependent upon the desired concentration ofthe detergent used. Resistance 56 is likewise set at a point previouslydetermined by calibration, which point is dependent upon the temperatureof the body of wash solution I9. Since the grid 13 and plate 14 of tubeH are approximately 180 out of phase, an increase in the resistance ofthe solution, due to a decrease in concentration, causes a gradualincrease in the instantaneous voltages between the grid 13 and cath ode12 which in turn causes a decrease in the curr n flo hrou h theresjst 13 'Ihecon- 6. trolvoltage developed across resistor 14, applied acrossthe control grid 16 and cathode 15 of tube 12,- is suflicientzto preventtube I2 from firing before the concentration of the solution starts todecrease. When the decrease in voltage drop across-resistor 14',resulting from the increase in resistance'across the electrode 6|,reaches a critical value, depending upon the tube employed, the'controlgrid 16 loses control and the tube 12 fires which causes current to flowthrough the relay 82 which effects closing of the switch 54 causingcurrent to flow through the solenoid 48. The armature 48 of the solenoid48 is thus raised against the action of spring 49, to move plug 43 fromits seat 42.. Water in reservoir 40 along with that supplied theretothrough line flows through opening42 and spout 44, to the distributorplate 31, and flows in contact with the I detergent, the resultantsolution passing through passageway 35 into and through passageway 34,into the washer where it collects in tank 20. 7

As the concentration of the solution in tank 20 increases, theresistance across the electrode 6! decreases, and agradual decrease inthe instantaneous voltages between the grid 13 and cathode I2 of tube lloccurs, which causes an increase in the current flowing through resistor14'. The resultant increase in voltage appearing across the control grid16 and cathode 15 of tube 12 finally reaches a point where the controlgrid 16 resumes control and extinguishes the tube, stopping the currentflow through the relay 82, deenergizing it, and opening the switch 54,whereupon, under the influence of spring 49, valve stem 46 returns valveplug 43 to its seat 42. Water thereafter supplied through line 45 flowsfromreservoir 46 through overflow pipe 4| into and through passage 35and not to the body of detergent maintained in compartment 36 of thedispenser 21.

' If the controller has an auxiliary electrode as disclosed in saidco-pending application of Paul A. Keene, which type of controller should1 be used when using detergents which tend to foam,when the foam risesto a point such that it enters between the plates 63, 64 of theauxiliary electrode 62, the resistance in the arm 58 of the Wheatstonebridge is thereby reduced so that, as hereinabove described, valve plug43 is seated in seat 42 and the water flows through channel 35 and notthrough the body of deter gent. Hence, as long as foam is present at alevel such that it contacts the auxiliary electrode 62, no detergent isfed to the washer. When the foam dies down, the auxiliary electrode 62is left free'and clear, exerting no further effect on the controlelectrode 6| and permitting this electrode to maintain the concentrationof the detergent in the washer within the desired narrow limits.

It will be noted the dispenser of this invention uses solid detergent incompartment 36, as obtained from the package or barrel, thus avoidingthe necessity of preparing solutions or special physical forms ofdetergents such as pellets or tablets required in the operation of somedispensers. It will be further noted the dispenser is simple in designand can easily be fabricated; hence, it is of relatively low cost. Theonly mechanical movements involved in the dispenser are the movement ofthe valve plug 43 from a position where the water is discharged so thatit flows in contact with the solid detergent in compartment 36 to aposition where the water OW d r t y and thrOll 91 31 1 3 5; h nc themaintenance: cost of: the dispenser; is: very smallt. Since the, supplyof detergent is controlled by small changes the;concen=tration orthebodyof: wash solution, the concentration. is maintained within narrowlimits,determined. to;v be most efiective for producinggeflicient-washing; Thisresults ina substantial saving of. detergent since feeding thereof doesnot take place: unless there is av demand for the detergent, In. otherwords, if. the demand for the detergent falls: off, the controlleroperates to interrupt. detergent feed if, on the.- other hand the demandfor the detergent increases, then the controller operates to increasethe time interval during which detergent is fed: to the washer, tomaintain the: desired concentration.

Due to the. howof water, preferably at. a. temperature of; about. 10.05F. or higher through: the discharge conduit 34. when there is nodemandfor. detergent, crystallization of detergent. within thedischarge.conduit is avoided since this water washes out any residual detergentsolution the discharge conduit 34= leading to-thei washer, thuspreventing this line from becoming plugged by crystallization,

In the operation of the. dispenser, ithas been found, the water fed tothe distributor plate 31 seldompenetrates, the body of solid detergenttherebelow to azdepth exceeding V2 to A; Accordingly, recrystallizationof detergent within the body of. solid detergentv inthe: dispenser islimited'tothi depth of the body or solid. detergent, Since therecrystallized: detergentis inall cases more. diiiicultly soluble thanthe original solid detergent, it will. be appreciated it is highlyadvantageous to limit the formation of. recrystallizeddetergent. to suchsmall depth;. if: the; recrystallized detergent were to extend all ofthe way to the base. of the: dispenser, this would materially reduce theefiiciency of the operation of the dispenser. Since certain changes maybe madein the aboveconstructionand different embodiments of theinventioncould be made. without departing from the scope thereof, it is intendedthat all matter contained in. the above description or shown-in theaccompanying; drawing shall. be interpreted as illustrative and not in.a. limiting sense.

What is claimed is: r r

1. In; a washer, receiving means for. a" body, of detergent solution, adispenser for supplying; detergent solution to said receiving meansv tomaintainthe concentration: of the bodyof detergent solution. thereinwithin narrow limits; said; dispenser. comprising in.cmbination, acontainer for solid detergent, a passageway communicating with saidreceiving means; a. sidewall: 01 said container having a portion.thereof provided: with ascreen. to place said container in.communication with said passageway, awater. reservoir'having an overflowpipe; leading; into. said. passage;- wayand a valve controlled v outlet.in: communication with said container; a; water. pipehaving itsdischarge outlet: disposed: to supply water to said water reservoir,means for: operating; said valve to cause water supplied to said;reservoir to flow therefrom through.- said: container in contact withthe. solid; detergent, the: resultant. solution flowingthrough. saidscreen: into, saidpassagewayand thence into saidlreceivingsmeams meansfor closing said valve so that the waterfflows from said reservoirthrough said overflow pipe directly 'tosaid passagewayandflows-therethrough into said receiving means and a controller responsiveto changes in the concentration of. saidbody of solutionto effect theoperation of: said valve. to cause the water tofiow in con,- tact withsaidgsolid, detergent and. the resultant solution to flow into saidreceiving means when the concentration of said-body of solution. fallsbelow a. predetermined value, and to cause said water to flow throughsaid overflow pipe, into and through said passageway; and thence intosaid receiving means when the. concentration. of said body of solution.-isrestored to said predetermined value:

2. A dispenser for detergenttomaintain the concentration of a. body ofdetergent solution within: narrow limits; comprising, in combination,receiving means. for saidbody of detergent. solution, a container forsoliddetergent, a passage.- way communicating with said. receiving,means, aside wall ofsaid container. having a portion thereof providedwith a. screen to place said container in communication with saidpassage.- way, meansfor supplying water to said container whereby thewater dissolves a portion of said solid detergent and the resultantsolution flows through said screen; into said passageway and thence:into: said receiving means for said body of detergent solution, meansfor diverting said water supply so. that the water is fed directly tosaid passageway and flows therethrough into said receiving means, theratev of supply of water to said. passageway being; such that the volumeof water passed directly into said passageway and thence into saidreceiving means has no appreciable efiect. on the concentration of saidbody or" detergent solution in. said receiving means, and a controllerresponsive to-changes in the concentration of said, bodyofv detergentsolution to affect. the operation of said water supply to cause water toflow in. contact with said. solid detergent when: theconcentration ofsaid body of detergent solution falls. below a predetermined valueand-zto cause the water to flow directly toand. through said passagewayinto said. receiving means for said body of' detergent solution whenthe, concentration of-:'said body of detergent solution" is; restoredtosaid predetermined value.

3. A dispenser for detergent to, maintain the concentration of abody ofdetergent solution within. narrow limits, comprising, in combination,receiving means .for saidbody of detergent solution-,a container havinga compartment for solid detergent, a passageway contiguous to: saidcompartment. and. separated from said compartment bya perforated wallthereby placing said compartment inscommunication with: said passagewaythrough said perforations, a discharge conduit leading. from. saidpassageway to said receiving means for said body: of. detergentsolution, means for'supplying a stream ofv liquid" to the body of soliddetergent in said compartment, the liquid flowing in contact: with.saidsolid detergent; and. the resultant solution flowing into andthroughsaidpassageway and said discharge conduit: an'dthence. intosaidreceiving means for said.- body of; detergentsolution, means for,diverting. the; flow or said stream. of liquid to cause said liquidtofiow through saidxpassageway With.- out. flowing in contact with said.solid detergent insaid compartment, the liquid flowing from saidpassagewaythrough said discharge conduit into said receiving means forsaid body of detergent solution and thus flushing out and removing fromsaid passageway and said discharge conduit any solid --'detergentdeposited therein, and acon- 9 troller responsive to changes in theconcentration of said body of detergent solution to affect the operationof said liquid supply to cause the liquid to flow in contact with saidsolid detergent when the concentration of said body of detergentsolution falls below a predetermined Value and to cause the liquid toflow directly to and through said passageway and discharge conduit intosaid receiving means for said body of detergent solution when theconcentration of said body of detergent solution is restored to saidpredetermined value.

4. A dispenser for detergent, comprising, in combination, a cylindricalcontainer, an arcuate perforated wall disposed in said container toseparate the container into a compartment and a contiguous passageway,said compartment occupying a major portion of the volume of saidcontainer and adapted to receive solid detergent, receiving means for abody of detergent solution, a discharge conduit leading from saidpassageway to said receiving means, means positioned above saidpassageway for supplying water to the top surface of the body of soliddetergent, said water flowing in contact with said solid detergent andthe resultant solution flowing into and through said passageway anddischarge conduit into said receiving means for said body of detergentsolution, means for diverting the water flow to cause it to flow throughsaid passageway and said discharge conduit into said receiving meanswithout flowing in contact with the solid detergent in said compartment,whereby said water flushes out and removes from said passage- Way andsaid discharge conduit any solid detergent deposited therein, and acontroller responsive to changes in the concentration of said body ofdetergent solution to aifect operation of said water supply to cause thewater to flow in contact with said solid detergent when theconcentration of said body of detergent solution falls below apredetermined value and to cause the water to flow directly to andthrough said passageway and said discharge conduit into said receivingmeans for said body of detergent solution when the concentration of saidbody of detergent solution is restored to said predetermined value.

5. A dispenser for detergent to maintain the concentration of a body ofdetergent solution wthin narrow limits, comprising, in combination,receiving means for said body of detergent solution, means for supplyingwater to said dispenser, a container for solid detergent, a passagewaycommunicating with said receiving means, a side wall of said containerhaving a portion thereof 16 provided with a screen to place saidcontainer in communication with said passageway, water conduitmeans forpassage of water from said water supply means directly to saidpassageway and to said container for solid detergent, said water conduitmeans which supplies water directly to said passageway supplying saidwater in amount such that the volume of water delivered to saidreceiving means has no appreciable effect on the concentration of saidbody of detergent solution in said receiving means, means forcontrolling passage of water through said water conduit means, wherebywater supplied to said container for detergent dissolves a portion ofsaid solid detergent and the resultant solution flows through saidscreen into said passageway and thence into said receiving means forsaid body of detergent solution and water supplied from said watersupply means directly to said passageway flows therethrough and into-said receiving means, and a controller responsive to changes in theconcentration of said body of detergent solution and effecting theoperation of said means for controlling the passage of water throughthat portion of said water conduit means supplying water to saidcontainer for detergent to cause water to flow in contact with saiddetergent when the concentration of said body of detergent solutionfalls below a pre determined value and to discontinue this flow of waterin contact with the solid detergent so the water from said water supplyflows directly to and through said passageway and into said receivingmeans for said body of detergent solution when the concentration of saidbody of detergent solution is restored to said predetermined value.

JAMES K. FARRELL.

PAUL A. KEENE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,799,051 Le Baron Mar. 31, 19311,928,128 Guth Sept. 26, 1933 1,945,351 Grafton Jan. 30, 1934 1,951,426Littler Mar. 20, 1934 1,991,388 Healy Feb. 19, 1935 1,995,318 MerrillMar. 26, 1935 2,278,769 Chayie Apr. 7, 1942 2,370,609 Wilson et al Feb.27, 1945 2,377,363 Noble June 5, 1945 2,392,026 Cram Jan. 1, 1946

